Containers, such as small refrigerators, coolers or chests for maintaining food items cool or warm, which obtain their cooling or heating capabilities through a thermoelectric device, are known in the art. Most prior art thermoelectrically powered containers are provided with a power unit permanently positioned in one of the walls thereof. The unit often includes two sets of extruded, planar, heat exchanging fins, one set of fins being exposed to and often extending into the container and the other set of fins being exposed to ambient conditions.
A conventional thermoelectric semiconductor device is positioned between the heat exchanging fins. As is known in the art, when direct current is passed in one direction through the device, one of the sets of fins is caused to be heated while the other set of fins is cooled. When the current is reversed, the other set of fins is heated and the first set of fins is cooled. In the container cooling mode, fans positioned adjacent to the fins transmit cool air from the internal cool fins to the inside of the container and at the same time transfer warm air away from the outside fins. In the warming mode, the fans transmit the warm air from the internal fins to the inside of the container and at the same time transfer cool air away from the outside fins.
While such units satisfactorily selectively cool or heat the contents of a container, as desired, they are not without their problems. For example, in some units the internal fins extend far into the container, which fins take up valuable storage space, are subject to being damaged or contaminated by liquid spillage, and can cause a safety hazard to the user whose hands could be scratched by the fins. Moreover, when the power unit is in need of maintenance, it must be disassembled from the container which is not only a time-consuming task requiring technical skill but also such activity renders the container useless for its intended purpose until the power unit can be replaced.
In addition to contaminated or damaged fins, one of the problems potentially causing dissatisfaction with the operation of such devices is the accumulation of condensed moisture in the unit. Presently known forms of moisture removal only permit a dripping into the container itself, which is not conducive to the storage of items therein.
Other maintenance problems can arise by virtue of an overheating of the motor which drives the fans. Presently known thermoelectric units are not provided with any convenient means to maintain the motor cool to avoid the potential need to replace the same.
Finally, the cooling or heating efficiency relative to the size of known thermoelectric power units is lacking. By providing parallel, planar, adjacent fins, the ability of air being moved by the fans to find facile access to the space therebetween across the width of the fins is limited, and once the air is positioned and moved between the fins, the unobstructed path facilitates the disadvantageous quick movement therethrough which diminishes the heat exchange efficiency.
Thus, the need exists for a modular, more efficient, and more maintenance-free thermoelectric power unit, a need which is provided by the thermoelectric power module made in accordance with the concepts of the present invention.